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Filename Latest commit message Latest commit date
Milian Wolff 2538b9e245 perf report: Ensure the perf DSO mapping matches what libdw sees
In some situations the libdw unwinder stopped working properly.  I.e.
with libunwind we see:

~~~~~
heaptrack_gui  2228 135073.400112:     641314 cycles:
	            e8ed _dl_fixup (/usr/lib/ld-2.25.so)
	           15f06 _dl_runtime_resolve_sse_vex (/usr/lib/ld-2.25.so)
	           ed94c KDynamicJobTracker::KDynamicJobTracker (/home/milian/projects/compiled/kf5/lib64/libKF5KIOWidgets.so.5.35.0)
	           608f3 _GLOBAL__sub_I_kdynamicjobtracker.cpp (/home/milian/projects/compiled/kf5/lib64/libKF5KIOWidgets.so.5.35.0)
	            f199 call_init.part.0 (/usr/lib/ld-2.25.so)
	            f2a5 _dl_init (/usr/lib/ld-2.25.so)
	             db9 _dl_start_user (/usr/lib/ld-2.25.so)
~~~~~

But with libdw and without this patch this sample is not properly
unwound:

~~~~~
heaptrack_gui  2228 135073.400112:     641314 cycles:
	            e8ed _dl_fixup (/usr/lib/ld-2.25.so)
	           15f06 _dl_runtime_resolve_sse_vex (/usr/lib/ld-2.25.so)
	           ed94c KDynamicJobTracker::KDynamicJobTracker (/home/milian/projects/compiled/kf5/lib64/libKF5KIOWidgets.so.5.35.0)
~~~~~

Debug output showed me that libdw found a module for the last frame
address, but it thinks it belongs to /usr/lib/ld-2.25.so. This patch
double-checks what libdw sees and what perf knows. If the mappings
mismatch, we now report the elf known to perf. This fixes the situation
above, and the libdw unwinder produces the same stack as libunwind.

Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20170602143753.16907-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-06-05 14:18:05 -03:00
arch x86: fix 32-bit case of __get_user_asm_u64() 2017-05-21 18:26:54 -07:00
block
certs
crypto
Documentation ACPI updates for v4.12-rc3 2017-05-22 19:26:33 -07:00
drivers Merge branch 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux 2017-05-23 09:57:39 -07:00
firmware
fs Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-05-20 16:12:30 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-22 12:42:02 -07:00
init
ipc
kernel Power management updates for v4.12-rc3 2017-05-22 19:24:32 -07:00
lib
mm
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-05-22 12:42:02 -07:00
samples
scripts DeviceTree fixes for 4.12-rc: 2017-05-19 15:03:24 -07:00
security
sound
tools perf report: Ensure the perf DSO mapping matches what libdw sees 2017-06-05 14:18:05 -03:00
usr
virt
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Staging driver fixes for 4.12-rc2 2017-05-20 09:02:27 -07:00
Makefile Linux 4.12-rc2 2017-05-21 19:30:23 -07:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.